Cooling system auxiliary heater



Oct. 15, 1957 G. MIEDEMA v 2,810,059

COOLING SYSTEM AUXILIARY HEATER Filed April 19, 1956 INVENTOR. GERBEN MIEDEMA United States Patent Ofiice 2,810,059 Patented Oct. 15, 1957 COOLING SYSTEM AUXILIARY HEATER Gerben Miedema, Spokane, Wash. Application April 19, 1956, Serial No. 579,368

4 Claims. (Cl. 21938) My present invention relates to improvements in auxiliary heaters for liquid coolant circulatory systems and more particularly to an auxiliary heater operable by means of an electrical circuit having a circuit breaking safety device actuable when the temperature reaches a predetermined degree, for the purpose of heating the liquid coolant of an internal combustion engine.

The physical embodiment of my present invention is adapted to be included in and become a component part of a coolant circulatory system of an internal combustion engine, and may be conveniently located as found necessary for the respective applications.

The auxiliary heater is equipped with a tube through which the coolant may circulate, which is encased by an electrical heating element for a portion of its length and has a protective sealed housing enclosing the element. Preferably a switch which is releasably maintained in the on position is interposed in the electric circuit which energizes the heating element and is provided with a heat sensitive release mechanism for opening the switch when the temperature within the housing reaches a predetermined degree.

The primary object of the invention is to provide the auxiliary heater with a safety mechanism for shutting off the heater should the normal flow of the coolant material be blocked to the extent that the heat from the element may not be carried away and thus preclude the possibility of forming steam and pressure sufiicient to burst the coolant circulatory system. Further, in the event the coolant has drained from the system, the heat generated by the element will not be carried away, and the danger of tire and damaging of parts is precluded by means of the heat sensitive release mechanism which is adapted to open the electric circuit.

In the physical embodiment of my present invention, I utilize a minimum number of parts that are constructed and arranged with facility and at a minimum cost of production, to produce a durable and efficient accessory for the purpose defined.

The invention consists in certain novel features of construction and arrangement of parts as are hereinafter described and more specifically pointed out in the appended claims.

In the accompanying drawings I have illustrated a complete example of a physical embodiment of the invention constructed in accordance with one mode I have devised for the practical applications of the principles of the invention. It will, however, be understood that changes and alterations are contemplated in the exemplifying drawing and mechanical structures within the scope of my claims without departing from the principles of the invention. In the drawings like numerals refer to corresponding parts.

Figure l is a fragmentary View in perspective of a portion of an internal combustion engine and showing the auxiliary heater forming a component part of the circulatory cooling system thereof;

Figure 2 is a vertical cross section of my improved auxiliary heater upon a slightly enlarged scale;

Figure 3 is a fragmentary elevational view of the switch forming a part of the electrical circuit substantially on the planes indicated by lines 3-3 of Figure 4;

Figure 4 is a further enlarged fragmentary vertical cross section further detailing the switch and showing the association thereof with the housing and release mechanism taken substantially on the plane indicated by line 4-4 of Figure 3;

Figure 5 is a fragmentary lateral cross section taken on the plane indicated by line 5--5 of Figure 3; and

Figure 6 is a further enlarged fragmentary view partially in cross section showing the relationship of the switch actuating arm and the heat sensitive release mechanism.

In order that a complete understanding of the invention may be easily attained, I have shown a fragmentary view of portions of an internal combustion engine 10 having a conventional block 11 and removable head 12 which is secured by the head bolts 13 in clamping relationship to the head gasket 14 disposed between the block 11 and the head 12. An electrical generator G is shown as-- sociated with the motor 10.

As is commonly known, the internal combustion engine is provided with a liquid coolant circulatory system which includes a radiator (not shown) and a number of lengths of flexible hose 16, 17, 18, and 19, forming parts of the circulatory system and communicating with inlet and outlet openings 15 in the block 11 and head 12. There of course are other hose connections (not shown) communicating the circulatory passages of the engine 11 with the radiator and conventional heaters, etc., all of which are well known in the art and no further amplification thereof is required in this disclosure.

The auxiliary heater which is generally indicated by the numeral 20 is connected into the liquid coolant circulatory system of the internal combustion engine and forms a component part thereof. It is not necessarily connected in such a way that all of the fluid circulating must pass through the auxiliary heater 2%, but may be disposed in a secondary circuit fixed in parallel to some other passages of the circulatory system.

With reference now in greater detail to the auxiliary heater 20 per se, I have provided a central tube 21 of heat conducting material such as copper, which is adapted to communicate with the hoses as seen at 16 and 17, for example, so that the liquid coolant may circulate through the tube 21. In the drawing I have shown the lower end portion 21a of the central tube 21 as having applied thereto an angular elbow member 21b to facilitate connection of the hose 16 thereto. This however, is not a requirement to the practice of the present invention and may or may not be employed, as found desirable. Enclosing a portion of the central tube 21 is a heating element 22 which is adapted to be heated by electrical energy received from the generator G or other source such as a battery (not shown) through the electric cable 23.

A housing 24 encases the heating element 22 in spaced relationship thereto and an insulating material 25 is disposed between the heating element 22 and the housing 24. Heads or end pieces 26 close the open ends of the housing and completely seal the housing with regard to the central tube 21.

The housing 24 is provided with an aperture 27 in one side thereof and a switch cover 28 forming a component part of the housing 24 is releasably secured thereto by means of metal screws 29. A rubber or other type seal 30 is disposed intermediate the two housing portions 24 and 28 to maintain the seal of the housing, the purpose of which is to prevent fluids such as water, oil, and gasoline from entering into the housing and destroying the insulating qualities of the insulation 25 and the electrical insulation of the heater 22. Within the housing I dispose an off-on switch 31 which has extending along its longitudinal side edges outwardly extending beads 32 disposed substantially midway the height of the switch body 33.

peripheral edge portions of the openings 27 .of the housing 24. Therefore it is obvious that no additional fastening means is required to securethe switch 31 to the housing 24.

The switch body 33 is provided with an off-on switching device here shown to be a resilient leaf or arm 35 which carries a contact point 36 on its lowerface which is adapted to be moved alternately into and out of electrical contact with a second contact 37 carried by the body 33 and to which a wire 37a is connected. At its opposed end, wire 37a is electrically connected to energize the heating element 22.

A block of insulating material 38 is secured to the arm 35 on its upper face at the location of the contact 36 and extends laterally therefrom in overlying relationship to the outer or free end portion ofa spring arm 39 which is fixed at 40 to the switch body 33. The arm 39 has a normal upward bias sufficient to contact the insulation block 38 and lift the arm 35 so that the contacts 36 and 37 are separated, thus forming the off-on switch of the electrical circuit and obviously biasing the switch toward the ofi" position.

One wire 23:: of the supply cable 23 is electrically connected to the arm 35 which is made of conductive material and is electrically connected to the contact 36. The other wire 23b is soldered or otherwise secured to a connector 40 to which a second wire 41 of the heater element 22. is connected. Therefore, obviously, when the contacts 36 and 37 are closed, a complete circuit is made from the supply cable 23 through the switch 31, the electrical heater 22, and back to the supply cable 23, thus providing means for heatingthe element 22. When the biasing arm 39 is released and is raised, the contacts 36 and 37 are separated, thusw breaking the circuit through the heating element 22 and preventing its being heated.

Carried by the housing 24, I provide a bracket 42 which is here shown to be riveted or otherwise secured to one head 26 but which may be secured to any convenient.

bracket 42 and prevent relative rotation thereof so long as the metal 46 is not fused or melted. For example, say the metal 46 fuses at a temperature of 190 degrees. Then the disc 44 will be rigidly secured to the bracket 42 atall temperatures below 190 degrees, but when the tempera-- ture of the fusible metal 46 is increased to or above 190 degrees the metal 46 fuses and permits the disc 44 to rotate about the journal pin 43.

v On its free end the biased arm 39 is provided with an inverted U-shaped extension 47 which terminates in a tongue 48 disposed to cooperate with the serrations of the disc 44. As seen in Figure 6, the extension 47 is flexible from the full line position to the dotted line position, and the tongue 48 may thus be disposed in the serrations of the disc 44 by merely depressing the extension 47 downwardly in the direction of the arrow 49. This will remove liftingpressure from the insulation block'38 and permit the contacts36 and 37 to engage, forming an' electrical connection and completing the circuit; As: long as the tongue 48. is engaged in the serrationsof the disc 44, the circuit is complete, but when for any reason the temperature within the housing 24 is increased above the fusing. temperature of the metal .46., the disc, 44- isreleasedv and the bias pressure of the arm39 will causethe. extension 47 to raise in. the opposite direction from. the arrow 49, the tongue 48 eifectingrotation of thedisc 44 about the journal pin 43 and causing separation of the points 36 and 37. Of course, the disconnection of the electrical circuit will cause the heating element at once to commence cooling and when the temperature within the housing 24 is reduced below the fusing temperature of the metal 46, it will again set and solder the disc 44 to the bracket 42, whereupon the switch may be again reset by depressing the extension 47.

Since it is desirable that the housing be maintained in sealed condition, I have provided a plunger 50 which extends through the housing portion 28 and is disposed above the extension 47 as seen in Figure 4. An annular outstanding rib 51 protects the outer end of the plunger 50 and prevents accidental striking thereof, but yet with a relatively small implement such as a pencil or even a small finger of a person, the plunger may be depressed so that the extension 47 may be shifted and the tongue 48 may engage the serrations 45 of the disc 44, thus again resetting the normally closed or on switch which is biased toward an open or o position.

A leaf spring 52 is riveted or otherwise secured at 53 to the housing portion 28 andvmaintains the plunger 50 in a raised position so that the action of the biased arm 39 is not inhibited by the necessity of lifting the plunger 50.

Having thus described my invention, I claim as new and desire to secure by Letters Patent of the United States the following:

1. An auxiliary heater for a liquid coolant circulatory system of internal combustion engines comprising a central tube of heat conveying material to form a component part of the circulatory system; an electrical circuit including aheating element encasing a portion of the tube; a sealed housing encasing said element and from which the end portions of said tube extend; said electrical circuit including an off-on switch disposed within said housing and biased toward a circuit opening off position; and a heat sensitive release mechanism including a fusible material initially holding said switch in the closed on position and adapted to release said switch upon said material being subjected to a fusing temperature.

2. The invention as defined in claim 1 wherein said release mechanism comprises a serrated disc rotatable about an axis fixed relative to said housing; said switch having a lip engaged in the serrations of said disc for holding the switch in the closed on position; and said fusible metal holding said disc against rotation with respect to said housing, whereby the switch is held in the closed position.

3. The invention as defined in claim 2 and including a manually operable reset plunger disposed to effect movementof said lip into engagement with the serrations of said disc, whereby the switch may be moved by said plunger to the closed position and held therein by said release mechanism subsequent to the fusing and solidifying of said fusible metal.

. 4. An auxiliary heater for a liquid coolant circulatory system of internal combustion engines comprising a centraltube of heat conveying material forming a component part of the circulatory system; an electrical circuit including aheating element encasing a portion of the tube; and a sealed housing encasing said element and from which the end portions of said tube extend; said electrical circuit including an off-on switch biased toward a circuit opening off position; and a heat sensitive release mech' anism within said housing initially holding said switch in the closed on position and releasable upon being subjected to a predeterminedtemperature.

References Cited in the tile of this patent UNITED STATES PATENTS 1,683,920 Rohne Sept. 11, 1928 2,266,216 Kimberlin Dec."16, 1 941 2,286,340 Bulpitt June 16, 1942 2,681,407 Miedema June 15, 1954 2,707,217 Collins et al. Apr. 26, 1955 

